1 files changed, 80 insertions, 11 deletions

diff --git a/drivers/regulator/rpi-panel-attiny-regulator.c b/drivers/regulator/rpi-panel-attiny-regulator.c
index 00fb69efcfa2..a4af7adad2b5 100644
--- a/drivers/regulator/rpi-panel-attiny-regulator.c
+++ b/drivers/regulator/rpi-panel-attiny-regulator.c
@@ -27,18 +27,28 @@
 #define REG_POWERON	0x85
 #define REG_PWM		0x86
 
+struct attiny_lcd {
+	/* lock to serialise overall accesses to the Atmel */
+	struct mutex	lock;
+	struct regmap	*regmap;
+};
+
 static const struct regmap_config attiny_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
+	.disable_locking = 1,
 	.max_register = REG_PWM,
 	.cache_type = REGCACHE_NONE,
 };
 
 static int attiny_lcd_power_enable(struct regulator_dev *rdev)
 {
+	struct mutex *lock = rdev_get_drvdata(rdev);
 	unsigned int data;
 	int ret, i;
 
+	mutex_lock(lock);
+
 	regmap_write(rdev->regmap, REG_POWERON, 1);
 	msleep(80);
 
@@ -63,33 +73,49 @@ static int attiny_lcd_power_enable(struct regulator_dev *rdev)
 	 */
 	regmap_write(rdev->regmap, REG_PORTA, BIT(2));
 
+	mutex_unlock(lock);
+
 	return 0;
 }
 
 static int attiny_lcd_power_disable(struct regulator_dev *rdev)
 {
+	struct mutex *lock = rdev_get_drvdata(rdev);
+
+	mutex_lock(lock);
+
 	regmap_write(rdev->regmap, REG_PWM, 0);
 	regmap_write(rdev->regmap, REG_POWERON, 0);
 	msleep(30);
+
+	mutex_unlock(lock);
+
 	return 0;
 }
 
 static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
 {
+	struct mutex *lock = rdev_get_drvdata(rdev);
 	unsigned int data;
 	int ret, i;
 
+	mutex_lock(lock);
+
 	for (i = 0; i < 10; i++) {
 		ret = regmap_read(rdev->regmap, REG_POWERON, &data);
 		if (!ret)
 			break;
 		usleep_range(10000, 12000);
 	}
-	if (ret < 0)
+	if (ret < 0) {
+		mutex_unlock(lock);
 		return ret;
+	}
 
-	if (!(data & BIT(0)))
+	if (!(data & BIT(0))) {
+		mutex_unlock(lock);
 		return 0;
+	}
 
 	for (i = 0; i < 10; i++) {
 		ret = regmap_read(rdev->regmap, REG_PORTB, &data);
@@ -98,6 +124,8 @@ static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
 		usleep_range(10000, 12000);
 	}
 
+	mutex_unlock(lock);
+
 	if (ret < 0)
 		return ret;
 
@@ -125,10 +153,13 @@ static const struct regulator_desc attiny_regulator = {
 
 static int attiny_update_status(struct backlight_device *bl)
 {
-	struct regmap *regmap = bl_get_data(bl);
+	struct attiny_lcd *state = bl_get_data(bl);
+	struct regmap *regmap = state->regmap;
 	int brightness = bl->props.brightness;
 	int ret, i;
 
+	mutex_lock(&state->lock);
+
 	if (bl->props.power != FB_BLANK_UNBLANK ||
 	    bl->props.fb_blank != FB_BLANK_UNBLANK)
 		brightness = 0;
@@ -139,20 +170,27 @@ static int attiny_update_status(struct backlight_device *bl)
 			break;
 	}
 
+	mutex_unlock(&state->lock);
+
 	return ret;
 }
 
 static int attiny_get_brightness(struct backlight_device *bl)
 {
-	struct regmap *regmap = bl_get_data(bl);
+	struct attiny_lcd *state = bl_get_data(bl);
+	struct regmap *regmap = state->regmap;
 	int ret, brightness, i;
 
+	mutex_lock(&state->lock);
+
 	for (i = 0; i < 10; i++) {
 		ret = regmap_read(regmap, REG_PWM, &brightness);
 		if (!ret)
 			break;
 	}
 
+	mutex_unlock(&state->lock);
+
 	if (ret)
 		return ret;
 
@@ -174,22 +212,30 @@ static int attiny_i2c_probe(struct i2c_client *i2c,
 	struct regulator_config config = { };
 	struct backlight_device *bl;
 	struct regulator_dev *rdev;
+	struct attiny_lcd *state;
 	struct regmap *regmap;
 	unsigned int data;
 	int ret;
 
+	state = devm_kzalloc(&i2c->dev, sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	mutex_init(&state->lock);
+	i2c_set_clientdata(i2c, state);
+
 	regmap = devm_regmap_init_i2c(i2c, &attiny_regmap_config);
 	if (IS_ERR(regmap)) {
 		ret = PTR_ERR(regmap);
 		dev_err(&i2c->dev, "Failed to allocate register map: %d\n",
 			ret);
-		return ret;
+		goto error;
 	}
 
 	ret = regmap_read(regmap, REG_ID, &data);
 	if (ret < 0) {
 		dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
-		return ret;
+		goto error;
 	}
 
 	switch (data) {
@@ -198,7 +244,8 @@ static int attiny_i2c_probe(struct i2c_client *i2c,
 		break;
 	default:
 		dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data);
-		return -ENODEV;
+		ret = -ENODEV;
+		goto error;
 	}
 
 	regmap_write(regmap, REG_POWERON, 0);
@@ -208,24 +255,45 @@ static int attiny_i2c_probe(struct i2c_client *i2c,
 	config.regmap = regmap;
 	config.of_node = i2c->dev.of_node;
 	config.init_data = &attiny_regulator_default;
+	config.driver_data = &state->lock;
 
 	rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);
 	if (IS_ERR(rdev)) {
 		dev_err(&i2c->dev, "Failed to register ATTINY regulator\n");
-		return PTR_ERR(rdev);
+		ret = PTR_ERR(rdev);
+		goto error;
 	}
 
 	props.type = BACKLIGHT_RAW;
 	props.max_brightness = 0xff;
+
+	state->regmap = regmap;
+
 	bl = devm_backlight_device_register(&i2c->dev, dev_name(&i2c->dev),
-					    &i2c->dev, regmap, &attiny_bl,
+					    &i2c->dev, state, &attiny_bl,
 					    &props);
-	if (IS_ERR(bl))
-		return PTR_ERR(bl);
+	if (IS_ERR(bl)) {
+		ret = PTR_ERR(bl);
+		goto error;
+	}
 
 	bl->props.brightness = 0xff;
 
 	return 0;
+
+error:
+	mutex_destroy(&state->lock);
+
+	return ret;
+}
+
+static int attiny_i2c_remove(struct i2c_client *client)
+{
+	struct attiny_lcd *state = i2c_get_clientdata(client);
+
+	mutex_destroy(&state->lock);
+
+	return 0;
 }
 
 static const struct of_device_id attiny_dt_ids[] = {
@@ -240,6 +308,7 @@ static struct i2c_driver attiny_regulator_driver = {
 		.of_match_table = of_match_ptr(attiny_dt_ids),
 	},
 	.probe = attiny_i2c_probe,
+	.remove	= attiny_i2c_remove,
 };
 
 module_i2c_driver(attiny_regulator_driver);